A special care baby unit has been shut down after four babies tested positive for deadly MRSA.

Doctors at Wycombe Hospital in Bucks immediately isolated the days-old babies and closed the unit to new admissions. Hospital bosses believe the superbug, which kills around 1,500 people in England and Wales every year and is resistant to many antibiotics, came in when a baby was transferred from another hospital.

Mrsa is spread by contact with hands, bedding, clothes or equipment and last night a hospital source said: "There are no more vulnerable patients in the hospital than those in the special care unit. It should be the cleanest part of the entire hospital, so for this to happen is totally unacceptable. Clearly hygiene standards have not been good enough."

Last night the children were said to be responding well.

A hospital spokesman said that the bug had been found on babies' skin but had not infected them.